Single antenna co-channel interference cancellation (SAIC) is important, especially for Global System for Mobile communications/Enhanced Data (GSM/EDGE) downlinks. In field trails, tremendous capacity gains have recently been demonstrated [1] 3G Americas, “SAIC and synchronized networks for increased GSM capacity,” particularly for synchronized networks in urban areas. As a consequence, the upcoming GSM/EDGE release will be tightened with respect to interference cancellation.
One of the most challenging tasks is the design of the interference canceller, especially if, due to cost, volume, power consumption, and design aspects, only one receive antenna is available. Most interference cancellers fail if the number of receive antennas do not exceed the number of co-channels [2] J. H. Winters, “Optimum combining in digital mobile radio with co-channel interference,” IEEE J. Sel. Areas Commun. vol. 2, no. 4, pp. 528-539, 1984, [3] A. M. Kuzminskiy and D. Hatzinakos, “Semiblind estimation of spatio-temporal filter coefficients based on a training-like approach,” IEEE Signal Processing Letters, vol. 5, no. 9, pp. 231-233, September 1998, [4] A. M. Kuzminskiy, C. Luschi, and P. Strauch, “Comparison of linear and MLSE-spatio-temporal interference rejection combining with an antenna array in a GSM System,” in Proc. IEEE Veh. Techn. Conf. '00, Tokyo, Japan, pp. 172-176, May 2000.
A receiver structure with linear filtering and decoupled non-linear detection has been studied in [5] D. Giancola, U. Girola, S. Parolari, A. Picciriello, U. Spagnolini, and D. Vincenzoni, “Space-time processing for time varying co-channel interference rejection and channel estimation in GSM/DCS systems,” in Proc. IEEE Veh. Techn. Conf. '99, May 1999, [6] S. Ariyavistakul, J. H. Winters, and N. R. Sollenberger, “Joint equalization and interference suppression for high data rate wireless systems,” IEEE J. Sel. Areas Commun. vol. 18, no. 7, pp. 1214-1220, July 2000, [7] R. Friedman and Y. Bar-Ness, “Combined channel-modified adaptive array MMSE canceller and Viterbi equalizer,” in Proc. IEEE Veh. Techn. Conf. '01, pp. 209-213, 2001, [8] A. L. F. de Almeida, C. M. Panazio, F. R. P. Cavalcanti, and C. E. R. Fernandes, “Space-time processing with a decoupled delayed decision-feedback sequence estimator,” in Proc. IEEE Veh. Techn. Conf. '02, Birmingham, Ala., USA, May 2002, [9] K. Kim and G. L. Stuber, “Interference cancelling receiver for range extended reception in TDMA cellular systems,” in Proc. IEEE Veh. Techn. Conf. '03, October 2003 using multiple receive antennas. A special case of linear filtering in conjunction with a memory-less detector has been investigated in [10] B. R. Petersen and D. D. Falconer, “Suppression of adjacent-channel, co-channel, and intersymbol interference by equalizers and linear combiners,” IEEE Trans. Commun. vol. 42, no. 12, pp. 3109-3118, December 1994, [11] H. Trigui and D. T. M. Slock, “Cochannel interference cancellation within the current GSM standard,” in Proc. IEEE ICUPC '98, pp. 511-515, 1998, [3], and [4] for the case of multiple receive antennas. Further, there is known Kammeyer's pre-filter [12] K. D. Kammeyer, “Time truncation of channel impulse responses by linear filtering: A method to reduce the complexity of Viterbi equalization,” AEÜ, vol. 48, no. 5, pp. 237-243, 1994, which is designed in order to truncated a single InterSymbol Interference (ISI) channel, but which does not take Co-Channel Interference (CCI) into account. A similar pre-filter has also been proposed by Al-Dhahir and Cioffi [13] N. Al-Dhahir and J. M. Cioffi, “MMSE decision feedback equalizers: Finite-length results,” IEEE Trans. Inform. Theory, vol. 41, no. 4, pp. 961-975, July 1995, for the case of Gaussian noise plus interference. In the present case, focus shall be on a few numbers of dominant interferers, which is the typical case in cellular networks, i.e., on non-Gaussian interference. [14] R. Meyer, R. Schober, and W. Gerstacker, EP 1221780 A1, published July 2002 discloses a pre-filter with real-valued processing, being designed according to the principles established in [11]